This application is related to the application entitled xe2x80x9cMETHOD FOR INTRODUCING HARMONICS INTO AN AUDIO STREAM FOR IMPROVING THREE DIMENSIONAL AUDIO POSITIONINGxe2x80x9d filed concurrently herewith, in the name of the same inventor, and assigned to the same assignee as this Application. The disclosure of the above referenced application is hereby incorporated by reference into this application.
1. Field of the Invention
This invention relates generally to audio sounds and, more specifically, to a method for customizing the HRTF (Head Related Transfer Function) of individual listeners to provide more convincing and pleasurable three dimensional audio works.
2. Description of the Prior Art
Over the years, the audio industry has introduced new technologies that have steadily improved the realism of reproduced sounds. The 1940""s monaural high fidelity technology led to the 1950""s stereo. In the 1980""s, digitally based stereo was introduced to improved the realism of reproduced sounds. Recently, spatial enhanced sound systems have come into existence. These systems give the listener a 180 degree, planner two dimensional presentation of sound. Listeners perceive a xe2x80x9cwidenedxe2x80x9d or xe2x80x9cbroadenedxe2x80x9d soundstage where sounds apparently are not limited to the space between the two speakers as in a conventional stereo system. Although offering more depth than conventional stereo systems, it falls short of providing full and realistic three-dimensional sounds.
Positional three-dimensional sound systems recreate all of the audio cues associated with a real world, and sometimes surrealworld, audio environment. The big difference between spatial enhanced and positional three-dimensional sound is that spatial sound uses two tracks and must evenly apply signal processing to all sounds on the track. Positional three-dimensional audio processes individual sounds according to Head Related Transfer Function (HRTF) techniques and then mixes the processed individual sounds back together before final amplification. This enables imbuing individual sounds with sufficient spatial cuing information to present an accurate, convincing rendering of an audio soundscape just as one would hear it in real life.
The problem with current positional three-dimensional sound systems is that it is not effective for all people. Each individual has a different HRTF based on the size and shape of their head and ears. An average HRTF will be convincing to most, but not all listeners. The further the individual""s HRTF is from the average, the less convincing the experience. Even for those individuals where three-dimensional sound is effective, a majority of them will feel that the average function is realistic but not truly convincing because all of the audio cues do not correspond for them.
Therefore, a need existed to provide a method of improving three-dimensional sound for all listeners. The method must customize the three-dimensional sound for each listener in order to provide realistic and convincing three-dimensional sound for each listener. Customization can be achieved by playing a series of sample sounds and having each listener identify where the sound came from. The test will identify for each listener which audible positional cues are most important, how frequency changes are interpreted as position, and what effects are most convincing and pleasurable for each listener. The results can then be applied to all three-dimensional sounds providing all listeners an optimum audio experience.
In accordance with one embodiment of the present invention, it is an object of this invention to provide a method of improving three-dimensional sound for all listeners.
It is another object of the present invention to customize three-dimensional sounds for each listener in order to provide realistic and convincing three-dimensional sounds for each listener.
It is another object of the present invention to customize three-dimensional sounds by playing a series of sample sounds and having each listener identify where the sound came from in order to identify for each listener which audible positional cues are most important, how frequency changes are interpreted as position, and what effects are most convincing and pleasurable for each listener.
In accordance with one embodiment of the present invention, a method of customizing an HRTF (Head Related Transfer Function) for an individual listener to provide the individual listener an optimum realistic audio experience. The method comprises the steps of: playing a series of positional test sounds for the individual listener; identifying positions of each of the series of positional test sounds by the individual listener; and modifying the HRTF to obtain the optimum realistic audio experience for the individual listener based on the individual listener identifying positions of each of the series of positional test sounds.